Automatic Processing Of Mountain Contours In The Digital Topographic Map Of The Whole Field

With the rapid development of science and technology,topographic mapping has gradually entered digital and automation.In digital topographic maps,contours are used to express terrain changes.Therefore,in the whole field digital topographic map,the correct mapping of contours is an important factor in the quality of topographic maps.For the mountainous areas,the terrain is ups and downs,the terrain changes complexly,and there are many topographic features such as ridge lines and valley lines.It is difficult to measure in the field,and the drawing in the industry is difficult.The correct drawing of the contours is a pole.Complex work.This article has carried out research on this:(1)The principle of automatic drawing of contour lines is summarized,including traditional triangulation growth algorithm,edge-based triangulation network algorithm,contour tracking and contour smoothing.The steps and precautions for drawing contour lines using Southern CASS are elaborated,mainly including establishing DTM,modifying triangulation and drawing contour lines.(2)The problem of incorrectly drawing the contours of digital topographic maps has been studied and analyzed from both internal and external industries.Among them,the problems of field observation include:the drawing of sketches,the method of measurement and the selection of feature points;The planar features and topographical features are elaborated in detail,and reasonable suggestions are given for these problems,which can improve the quality of the topographic map to a certain extent.(3)In the drawing of contour maps of mountain topographic maps,the drawing of ground lines is a complicated task.The error contour line generated by the undrawn ground line is analyzed,and an idea of automatically drawing the ground line based on the error contour is proposed.The.automatic search of the closed curve and the automatic extraction of the feature point information are realized by the program.The automatic connection with the feature points is used to realize the automatic drawing of the ground line,and the contour drawing is correctly drawn by human-computer interaction(4)Based on the problem of the contour line wearing the house,an idea of automatically adding the elevation point of the house is proposed.By extracting the corner coordinates of the house and the existing elevation point information,the existing elevation point information is automatically copied to the untested At the corner point,the automatic addition of the attribute information of the elevation point of the unmeasured corner point of the house is realized,which improves the production efficiency and quality of the topographic map to some extent.